The present invention relates to an image forming apparatus applied to an electronic copying machine, and more specifically to an image forming apparatus which comprises a photosensitive body holding electric charge, charging means for applying electric charge to the photosensitive body, exposure means for optically scanning an image of an original and exposing the photosensitive body charged by the charging means, thereby forming an electric charge pattern responsive to the original image, and developing means for developing the electric charge pattern formed on the photosensitive body by the exposure means.
In general, electronic copying machines copy an image of the original on to a paper sheet directly or on an enlarged or reduced scale.
Meanwhile, some of the contents of the original may be omitted as unnecessary in copying. In copying, however, conventional copying machines cannot selectively erase the unnecessary portions of the original image.